common exotropia
Introduction
Introduction to common exotropia Common exotropia (concomitantexotropia) is divided into primary and secondary, primary include oblique oblique, intermittent exotropia and constant exotropia. Secondary episodes include sensoryxotropia, which is caused by poor visual acuity and postoperative exotropia, which is caused by overcorrection after esotropia surgery. Most patients have an earlier onset age, 35% to 70% occur within 2 years of age, and the external oblique begins to be an oblique oblique, further developing intermittent exotropia and constant exotropia. This progression may be due to the increase in collective tension with age. And weaken related. basic knowledge Sickness ratio: 0.0001% Susceptible people: good for children Mode of infection: non-infectious Complications: refractive error
Cause
Common esotropia etiology
Anatomical factors, mechanical factors and innervation factors play a role in all common strabismus. Common exotropia is likely to play an important role in the innervation. In theory, the primary common exotropia comes from the collection and Separation caused by tension imbalance between the two, EMG studies prove that separation is an active physiological process, rather than simply collecting passive inhibition results, Duane first proposed that the external oblique is caused by the innervation imbalance, this imbalance disturbed The relationship between collection and separation.
Congenital anomalies (30%):
Congenital anomalies are not pure heredity. Congenital anomalies also include head injuries at birth. These strabismus are mostly caused by abnormal development of congenital extraocular muscles, abnormal development of extraocular muscles, or nerve paralysis that governs muscles. .
In addition, there are also genetic factors. The strabismus is not a member of the family, and this defect is often indirectly transmitted to the next generation of children. Generally, strabismus is called congenital strabismus within 6 months of birth. It does not have the basic conditions for establishing binocular vision, and it is the most harmful to the development of visual function.
Extraocular muscle abnormalities (30%):
Excessive or hypoplasia of an extraocular muscle, abnormal attachment point of the extraocular muscle, development of the eyelid, abnormality of the fascia structure of the iliac crest, etc., can lead to imbalance of muscle strength and strabismus. Because the development of children's body is still not perfect: children, especially infants and young children, the development of binocular monocular function is not perfect, can not coordinate the extraocular muscle well, any unstable factors can promote the occurrence of strabismus.
Other (20%):
Certain diseases may also cause strabismus in children, such as congenital eye cataracts and other organic diseases of the eyes may lead to strabismus in children.
Prevention
Common exotropia prevention
Let the children look at the distance from a distance, exercise the contraction ability of the rectus muscles outside the eye, and let the children look at the distance for a while on the balcony every day. When playing with children, whether it is eyes or toys, keep a certain distance from the eyes of children, at least 50 cm. The hanging toy on the baby bed should also be kept 50 cm away. Always change the sleeping position of the child and the hanging position of the toy. Do not fix the bedside lamp for a long time. Always change position. Children with obvious esotropia in preschool age must see an early diagnosis and wear glasses to correct myopia and amblyopia. Severe esotropia requires surgical correction.
Complication
Common strabismus complications Complications
Refractive error can weaken the innervation and affect the position.
Symptom
Common exotropia symptoms common symptoms myopic astigmatism ametropia amblyopia hyperopic diopter increase exotropia V sign
In addition to the interaction of the collection and separation mechanism, refractive error can weaken the innervation and affect the service position. In the past, it was considered that the external oblique was more common in myopia. According to the near-statistical data, the emmetropic eye and the hyperopia were not uncommon, only 8%~15. % is seen in myopia, Jjampolsky emphasizes that there is a clear relationship between astigmatism and exotropia. Because the degree of retinal image clarity is different, it can hinder fusion and is easily suppressed, so exotropia occurs.
Examine
Common exotropia
(1) Examination of binocular visual function: 1 The three-level situation in which the same vision machine is used in the country to check the binocular visual function; 2 Quantitative measurement of the stereoscopic function, the stereoscopic visual image is determined by the stereoscopic quantitative picture of the same machine or the random point stereogram of the Yans degree.
(2) Refractive examination: Atropine paralyzed ciliary muscle optometry, one is to understand whether there is amblyopia, and the other is to understand the relationship between strabismus and refraction.
(3) Determination of eye position and oblique angle: Determine which type of strabismus is used, and the size of the oblique angle must be checked for the surgical design.
(4) Eye movement examination: to judge the function of the extraocular muscles.
(5) Is there a compensatory head position: Different head postures can help diagnose which extraocular muscle paralysis.
(6) Determining the examination of the paralysis muscle: the red lens test or the Hes screen method.
(7) Pulling test: 1 Estimate postoperative diplopia and patient tolerance after preoperative traction; 2 Supported pull test: can understand whether there is mechanical contraction of the extraocular muscle or muscle spasm; Active contraction test: Understand the function of the muscles.
(8) Inspection of hidden obliqueity: Quantitative measurement is performed by using a hidden inclinometer.
(9) Detection of the collection of near points: to help diagnose muscle fatigue.
(10) AC/A Regulatory Set/Adjustment Ratio: Helps determine the relationship between strabismus and adjustment and set.
Diagnosis
Common exotropia diagnosis and differentiation
diagnosis:
Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.
Differential diagnosis:
First, the differential diagnosis of congenital common exotropia:
False exotropia
2. Perceptual exotropia
3. Eyeball Back Syndrome
4. Oculomotor paralysis
Second, the acquired common external strabismus should be differentiated from the external oblique.
